1. Field of the Invention
This invention relates to hydrocyclone separator apparatus. More particularly it relates to such apparatus whereof the individual hydrocyclone or "vortex" separators are useful in separating undesired components from a paper making fiber slurry and wherein the various manifolds for supplying the feed slurry thereto and for removing the separated slurry fractions therefrom are co-designed to fit together in multiple arrays of separators so that individual separators which malfunction may be readily removed and replaced.
2. Description of the Prior Art
Hydrocyclone separators are extensively used in the paper and pulp industry to remove the undesired components denser than the desired fibers, commonly called "heavier" or "heavies". The conventional separator long used for this purpose has an elongated tubular body which is at least in large part conical, with a tangential inlet for slurry to be treated at the larger end, an outlet from the smaller end and an outlet from the inlet end opposite the small end outlet. In this conventional separator, slurry fed into the larger end forms a helical vortex flowing along the inside wall toward the smaller end outlet. The inner portion of the vortex, however, reverses as it approaches the smaller end outlet, forming an inner vortex spiraling about an air core toward the inlet end, where it is removed, along with air from the core, through a central vortex finder, as the larger accept fraction. The smaller reject fraction of the slurry which discharges through the smaller end outlet contains the heavies which the centrifugal force of the vortex forces toward the wall and restrains from entering the inner vortex.
Such separators are efficient, although post treatment of the rejects fraction may be needed to recover a significant desired fraction which it inevitably contains. However, the accepts fraction, though essentially freed of heavies, still contains undesirable components which are not denser than the desired fibers, such as oversize fibers or fiber bundles, and if secondary fibers are a component of the slurry, bits of plastic, glue, gum and the like, commonly referred to as stickies. As disclosed in U.S. Pat. No. 3,306,444, such impurities, commonly referred to as "lighter" or "lights" (although some thereof may have the same density as that of desired fibers), tend to segregate toward the inner part of the reversing vortex. The patent provides a concentric inner vortex finder to separately remove the inner reversed vortex portion containing these impurities, a construction which has proved efficient in cleaning the accepts of these impurities.
A more recent alternative to this patented arrangement is used to clean the slurry of the lighter impurities after it has been cleaned of the heavies by preceding apparatus such as conventional two output separators described above. Such alternative separators now in successful commercial use are similar in body form to the conventional two way separators described above, but dispense with the feed end outlet and reversing vortex, providing instead a concentric outlet around the smaller end reject outlet. The good fibers, which, in view of pre-cleaning, now can be considered the "heavies", segregate under centrifugal force toward the wall and exit through the larger diameter outlet as the accepted fraction, while the remainder, to which the lights are segregated, is discharged as a smaller reject fraction via the inner outlet.
Such separators depend upon the centrifugal force which is generated by their vortex, which varies directly with speed at which the slurry travels its vortical path which, in turn, varies generally inversely with the diameter of the vortex. For this reason the modern art has trended toward small diameter cleaners in which the centrifugal force is high but the possible output for a given feed pressure is comparatively low, necessitating a large number of separators per treatment stage for the flow volume required by most paper or pulp mills. Since plugging problems also tend to be greater the smaller the diameter, a demand has arisen for interrelated design of separators and their manifolds in which the individual separators may be removed from their manifolds and replaced cleaned or with a new separator.
U.S. Pat. No. 3,861,532 discloses a system of separators and manifolds in which the individual separators may be placed in and removed from operative association with feed and output manifolds by insertion or withdrawal endwise through horizontally axially aligned round apertures lined with sealing material. In the system disclosed the separators may be removed without shutting off and draining the manifolds by attaching a new separator to one end of the separator to be replaced and pushing the assembly through the aligned sealing apertures until the new separator is in operative position and the now fully extruded initial separator can be detached.